The actor baited fans with a cheeky video that all but confirmed his role as Mysterio in the "Spider-Man: Homecoming" sequel.

Though Jake Gyllenhaal has been rumored to be playing the villain Mysterio in the upcoming “Spider-Man: Far From Home,” the actor all but confirmed the news in his very first Instagram post. In an amusing short video, Gyllenhaal is seen holding up an old copy of “The Amazing Spider-Man” comic, titled: “The Return of the Man Called Mysterio.” As he lowers the comic from the camera, an expression of shock and awe on his face, he wonders: “What the fuck?” Perhaps he’s been doing some character research? Gyllenhaal accompanied the short video with the following caption: “I just realized I’m not playing Spider-Man.”

Tom Holland will reprise his role as Peter Parker in the sequel to last year’s “Spider-Man: Homecoming.” Also returning are Zendaya, Marisa Tomei, and Tony Revolori. Michael Keaton will return as the villain Vulture, and Marvel regular Samuel L. Jackson will appear as Nick Fury. Jon Watts will also return to direct the sequel, which will be written by Jonathan Goldstein and John Francis Daley.

Jon Favreau, who directed the first two “Iron Man” films for Marvel, is rumored to be appearing as Happy Hogan.

So, who is Mysterio, and why is he so important to the MCU? As IndieWire’s Jamie Righetti explained then the rumors of Gyllenhaal’s role first surfaced: “In the comics, Mysterio is the alter ego of Quentin Beck, a Hollywood stuntman and FX wizard who dreams of becoming a big film star. For Beck these dreams aren’t obtainable, however. He’s a crap actor and his FX work isn’t going to get him anywhere, until he gets an idea to utilize his ability to create expert illusions to help him get a leg up on a life of crime.”

“Spider-Man: Far From Home” is set to hit theaters on July 9, 2019. Sony declined to comment about the casting announcement, though Gyllenhaal is currently listed on IMDb as playing Mysterio.